title: Evaluation of low back pain: comparative study between psychophysical methods.
abstract: OBJECTIVE
  The aims of this study were to validate the measurement of low back pain by different psychophysical methods and to compare different methods of pain measurement.
  
  
  METHODS
  This double-blind, randomized experimental study was realized in Brazil. The sample was 60 patients with low back pain, divided into two groups: group I (methylprednisolone 80 mg + 8 mL of 0.9% saline solution) and group II (methylprednisolone 80 mg + 5 mL of levobupivacaine without epinephrine + 3 mL of 0.9% saline solution), both using 10-mL syringes. The methods were the serial exploration and psychophysical (magnitude estimation, category estimation, and cross-modality matching).
  
  
  RESULTS
  Pain evaluation was carried out before the block and 30 minutes, 6, 12, and 24 hours after it. After 30 minutes of epidural block, the levobupivacaine group presented more significant reaction of reduction pain than the saline group. The magnitude and line-length scales were evaluated every period of time, showing no significant differences, except in 12 and 24 hours after the first block. The exponential function to every evaluation ranged from 0.87 to 1.00.
  
  
  CONCLUSIONS
  This research tries to bring to health care an original method for measuring low back pain. It is noteworthy that in the future, more research is needed to apply this method in clinical and scientific fields.
authors.affiliation: Department of Medicine, State University of Maringá, Maringá, Paraná, Brazil.
authors.forename: Orlando Carlos G
authors.initials: OC
authors.lastname: Colhado
authors.forename: Hilze B O
authors.initials: HB
authors.lastname: Moura-Siqueira
authors.forename: Débora Fernanda A
authors.initials: DF
authors.lastname: Pedrosa
authors.forename: Simone
authors.initials: S
authors.lastname: Saltareli
authors.forename: Talita de Cássia Raminelli
authors.initials: Tde C
authors.lastname: da Silva
authors.forename: Priscilla
authors.initials: P
authors.lastname: Hortense
authors.forename: Fátima A E
authors.initials: FA
authors.lastname: Faleiros Sousa
mesh_terms: D000328:Adult; D000700:Analgesics / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage / Q000031:analogs & derivatives; D004311:Double-Blind Method; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007268:Injections, Epidural; D000077554:Levobupivacaine; D017116:Low Back Pain / Q000188:drug therapy* / Q000523:psychology; D008297:Male; D008775:Methylprednisolone / Q000627:therapeutic use; D009407:Nerve Block / Q000379:methods; D010147:Pain Measurement / Q000379:methods*; D017288:Pain Threshold / Q000502:physiology; D011601:Psychophysics / Q000379:methods*
chemical_list: D000700:Analgesics; D000077554:Levobupivacaine; D008775:Methylprednisolone; D002045:Bupivacaine; D004837:Epinephrine
keywords: Assessment; Low Back Pain; Pain Management